New Ultra-Long-Acting Biologic, Exdensur (Depemokimab), Approved for Asthma

The FDA has approved Exdensur (depemokimab) as an add-on maintenance treatment for severe asthma characterized by an eosinophilic phenotype in adult and pediatric patients aged 12 years and older.

GSK’s new biologic drug is indicated for patients whose disease remains uncontrolled despite standard therapy, and is not intended for the relief of acute bronchospasm or status asthmaticus.

Severe asthma is a form of the disease that requires ongoing treatment with medium- to high-dose inhaled corticosteroids plus additional controller therapies, or that remains poorly controlled despite such treatment.

In many patients, the condition is driven by type 2 inflammation, which is associated with elevated levels of eosinophils, a type of white blood cell involved in airway inflammation.

In the US, an estimated 2 million people live with severe asthma, and about half continue to experience frequent exacerbations that can lead to emergency department visits or hospitalizations. CDC surveillance data from the 2021 National Health Interview Survey further show that nearly 40% of children and adults with current asthma reported at least one asthma attack in the prior 12 months.

Depemokimab is a monoclonal antibody designed to suppress type 2 inflammation. It has been engineered with an extended half-life, allowing for twice-yearly dosing. The therapy is administered as a subcutaneous injection and is intended for use alongside existing controller medications rather than replacing inhaled or systemic corticosteroids.

The approval is based on results from the Phase III SWIFT-1 and SWIFT-2 clinical trials, which evaluated depemokimab as an add-on therapy in patients with severe asthma receiving background treatment.

Across the two studies, nearly 800 participants were randomized to receive depemokimab or placebo in addition to medium- to high-dose inhaled corticosteroids and at least one additional controller.

In both trials, depemokimab significantly reduced the annual rate of asthma exacerbations compared with placebo over 52 weeks. SWIFT-1 showed a 58% reduction in exacerbation rate, while SWIFT-2 demonstrated a 48% reduction. Annualized exacerbation rates were 0.46 versus 1.11 in SWIFT-1 and 0.56 versus 1.08 in SWIFT-2 for depemokimab compared with placebo, respectively.

Secondary analyses showed fewer clinically significant exacerbations, defined as asthma attacks requiring hospitalization or emergency department care, among patients treated with depemokimab. A pre-specified pooled analysis of both trials demonstrated a 72% reduction in the annualized rate of exacerbations requiring hospitalization or emergency care compared with placebo over 52 weeks.

Across the studies, depemokimab was generally well tolerated, with a similar rate and severity of adverse events observed in the treatment and placebo groups.

Related: Advancing Asthma Management Through Innovation, Access and Equity

Poor adherence to long-term asthma therapies is a well-documented challenge. Treatment burden, limited education and challenges integrating medications into daily routines are among the key factors contributing to non-adherence in asthma care.

According to GSK, the approval provides clinicians with an additional biologic option for patients with eosinophilic severe asthma who continue to experience exacerbations despite existing therapies.

The Exdensur approval follows other recent regulatory developments involving GSK, including positive opinions from the Committee for Medicinal Products for Human Use (CHMP) in Europe for Nucala (mepolizumab; COPD) and Arexvy (RSV vaccine), as well as the recent FDA approval of Blujepa (gepotidacin) for uncomplicated urogenital gonorrhea.

Depemokimab has also received a positive CHMP opinion in Europe, with a regulatory decision expected in early 2026. Additional regulatory reviews are ongoing in other regions, including China and Japan.

In other recent developments in long-acting biologics, Generate:Biomedicines said its AI-designed investigational anti-TSLP antibody GB-0895 is expected to enter global Phase III testing (SOLAIRIA-1 and SOLAIRIA-2) in about 1,600 adults and adolescents with severe asthma. The studies will evaluate subcutaneous dosing every six months versus placebo over 52 weeks.

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